func drawPolyLine(img *image.RGBA, color color.Color, coords [][]float64) {
path := new(draw2d.Path)
for i, coord := range coords {
if i == 0 {
path.MoveTo(coord[0], coord[1])
} else {
path.LineTo(coord[0], coord[1])
}
}
gc := draw2dimg.NewGraphicContext(img)
gc.SetStrokeColor(color)
gc.Stroke(path)
}
func (r *Renderer) coordsAsPath(coords geom.Coordinates) *draw2d.Path {
path := new(draw2d.Path)
for i, point := range coords {
x, y, _ := r.m.Srs.Forward(point[0], point[1])
x, y = r.matrix.TransformPoint(x, y)
if math.IsNaN(x) || math.IsInf(x, 1) {
continue
}
if i == 0 {
path.MoveTo(x, y)
} else {
path.LineTo(x, y)
}
}
return path
}
// DrawClosedLine draws the line represented by the Points and closes it.
func DrawClosedLine(p Points, width, height float64, name string) {
// Initialize the graphic context on an RGBA image
dest := image.NewRGBA(image.Rect(0, 0, int(width), int(height)))
gc := draw2dimg.NewGraphicContext(dest)
// Set some properties
gc.SetStrokeColor(color.RGBA{0x44, 0x44, 0x44, 0xff})
gc.SetLineWidth(5)
paths := []*draw2d.Path{}
// Draw a path
for idx, point := range p[:len(p)] {
path := new(draw2d.Path)
path.MoveTo(float64(point.X), height-float64(point.Y))
if idx < len(p)-1 {
path.LineTo(float64(p[idx+1].X), height-float64(p[idx+1].Y))
} else {
path.LineTo(float64(p[0].X), height-float64(p[0].Y))
}
paths = append(paths, path)
}
gc.Stroke(paths...)
gc.FillStroke()
// Save to file
draw2dimg.SaveToPngFile(name, dest)
}
func Draw(img *image.RGBA, col color.RGBA, box shp.Box, shape shp.Shape) error {
poly, ok := shape.(*shp.Polygon)
if !ok {
return fmt.Errorf("cannot draw non-polygon shape")
}
gc := draw2dimg.NewGraphicContext(img)
gc.SetStrokeColor(col)
gc.SetLineWidth(1)
rect := img.Bounds()
dx := float64(rect.Max.X-rect.Min.X) / (box.MaxX - box.MinX)
dy := float64(rect.Max.Y-rect.Min.Y) / (box.MaxY - box.MinY)
for i, start := range poly.Parts {
end := len(poly.Points)
if i+1 < len(poly.Parts) {
end = int(poly.Parts[i+1])
}
part := poly.Points[start:end]
path := draw2d.Path{}
for j, p := range part {
x := ((p.X - box.MinX) * dx)
y := ((box.MaxY - p.Y) * dy)
if j == 0 {
path.MoveTo(x, y)
} else {
path.LineTo(x, y)
}
}
path.Close()
gc.Stroke(&path)
}
return nil
}
// FillStyle demonstrates the difference between even odd and non zero winding rule.
func FillStyle(gc draw2d.GraphicContext, x, y, width, height float64) {
sx, sy := width/232, height/220
gc.SetLineWidth(width / 40)
draw2dkit.Rectangle(gc, x+sx*0, y+sy*12, x+sx*232, y+sy*70)
var wheel1, wheel2 draw2d.Path
wheel1.ArcTo(x+sx*52, y+sy*70, sx*40, sy*40, 0, 2*math.Pi)
wheel2.ArcTo(x+sx*180, y+sy*70, sx*40, sy*40, 0, -2*math.Pi)
gc.SetFillRule(draw2d.FillRuleEvenOdd)
gc.SetFillColor(color.NRGBA{0, 0xB2, 0, 0xFF})
gc.SetStrokeColor(image.Black)
gc.FillStroke(&wheel1, &wheel2)
draw2dkit.Rectangle(gc, x, y+sy*140, x+sx*232, y+sy*198)
wheel1.Clear()
wheel1.ArcTo(x+sx*52, y+sy*198, sx*40, sy*40, 0, 2*math.Pi)
wheel2.Clear()
wheel2.ArcTo(x+sx*180, y+sy*198, sx*40, sy*40, 0, -2*math.Pi)
gc.SetFillRule(draw2d.FillRuleWinding)
gc.SetFillColor(color.NRGBA{0, 0, 0xE5, 0xFF})
gc.FillStroke(&wheel1, &wheel2)
}